1. Developing Coal Tar/ Petroleum Pitches
Melvin D. Kiser -
Marathon Ashland Petroleum Company
Robert H. Wombles -
Koppers Industries, Inc.

2. Discussion Topics
Introduction
Coal Tar and Petroleum Supplies
Coal Tar and Petroleum Pitch Manufacturing
Coal Tar/Petroleum Pitch Product Development

3. Introduction
First Coal Chemical Recovery Ovens Installed in the US in 1893
By 1915, By-product Ovens Accounted for 97% of Metallurgical Coke Produced in US
Since Then Coal Tar Pitch Has Been Binder of Choice for Aluminum, Commercial Carbon, and Graphite Industries

4. Introduction, cont.
Late 1980’s and 1990’s Closing of US Coke Ovens Accelerated Due to Economic and Environmental Pressures
Coke Oven Closures Resulted in Concern for Supply of Coal Tar Pitch and Strategies to Deal with Anticipated Shortage Being Sought

5. Introduction, cont.
Oil Industry As It Is known Today Began with the Discovery of Crude Oil in Ontario and Western Pennsylvania in 1850’s
Refineries Have Concentrated on Producing Transportation and Heating Fuel with Little Interest in Heavy Products Such as Pitch

6. Introduction, cont.
During 1960’s Some Refineries Began to Show Interest in Producing Petroleum Pitch and Some Were Successful in Producing High Aromaticity and Specific Gravity Pitches
Evaluation of These Pitches As Binder Pitches Has Given Mixed Results with Most Often Reported Shortcoming Being Higher Than Desired Carbon Consumption

7. Introduction, cont.
Future Use of Petroleum Pitches Will Probably Not Be Driven By Economics But Raw Material Availability and Regulations

8. Introduction, cont. Strategies to Deal with Shrinking Coal Tar Supply
Importing Coal Tar
Importing Coal Tar Pitch
Developing Processes to Improve Pitch Yield and Upgrade Non-conventional Coal Tars
Using Petroleum Pitches to Supplement Coal Tar Pitch Supply

9. Coal Tar and Petroleum Supplies

10. North American coal tar supplies to fall by 18% by 2005

11. North American Binder Pitch Demand

12. Petroleum Supplies
Yearly Supply of Coal Tar Is 6 MM Barrels (Less Than the Volume of Crude Oil Processed Each Day)
Yearly Supply of Potential Pitch Feedstocks Is 326 MM Barrels
Assuming Only 10% Available and Acceptable Results in Petroleum Pitch Yearly Feedstock Supply of 32.6 MM Barrels

13. Coal Tar and Petroleum Pitch Manufacturing

14. One Metric Ton of Coal Yields:
Coke Flow Diagram
One Metric Ton of Coal Yields:
70%
Solids
Blast Furnace Coke: kg
Coke Breeze: kg
Coke Oven
30% Gas + Liquid
Coke Oven Gas m3
Tar L
Ammonium Sulphate kg
Ammonia Liquor L
Light Oil L

15. PRODUCTION OF COAL TAR PITCH
Distillate
Stream
Steam
Flushing
Liquor
Heater
200°F
Distillation
Tower
Tar Feed
Tank
2000°F
Coal
gas
Tar
Steam
Decanter
Sludge
Pitch
Decanter
Coke Oven
Liquor

16. Coke Oven Thermal Cracking
CH2 CH2 CH2 CH3
1,095°C
No catalyst
+ C4

17. Petroleum Pitch Manufacturing
Many Petroleum Products Referred to as Pitch (Causes Confusion Among Non-Refiners)
Different Pitches Share Only Commonality of Being Black Solids at Room Temperature
Characteristics of Petroleum Pitches Determined by Feedstock and Processing to Produce
Reaction Step Used to Generate or Concentrate the High Molecular Weight Molecules

18. Common Petroleum Pitch Producing Processes
Solvent Deasphalting
Precipitation of High Molecular Weight and Aromaticity Molecules
Specific Gravity of 1.0 g/cc
Contains Non-aromatic Molecules and High Metals Levels
Oxidation
Little Incorporation of Oxygen in Product
Oxygen Generates Free Radicals Which Cause Polymerization
Products Typically Have Low Coking Values and High Viscosities
Thermal Processing
Thermal Processing Temperatures of 300°C to 480°C
Produces High Specific Gravity and Aromaticity Product

19. Crude Oil to Petroleum Pitch
Desalting & Dewatering
Atmospheric Distillation
Other Components
Pitch Feed Preparation
Fluid Catalytic Cracking
Vacuum Distillation
Primary Reaction Processes
Secondary Reaction Processes
Liquid Storage
Solidification
1. Feed preparation can consist of any one or a combination of blending, distillation, desulfurization and solids removal.
2. Primary reaction processes may consist of any one or a combination of solvent deasphalting, thermal processing, oxidation or catalytic reactions.
3. Secondary reaction processes may include distillation, desulfurization, oxidation or thermal soaking.

20. Petroleum Refinery Catalytic Cracking
CH2 CH2 CH2 CH3
CH3
540°C
Cracking catalyst
+ C3

21. Coal Tar/Petroleum Pitch
Aluminum Industry Experience with 100% Petroleum Pitch Not Acceptable
Suitable Petroleum Materials Must Be Identified (100 Materials Evaluated)
Commercial Testing Began in 1994
Small Performance Disadvantages Identified
Efforts to Improve Performance Successful
Most Economical Solution with Potential Plentiful Supply

22. Properties of Typical Pitches

23. Conclusions
Supply of Coal Tar in North America Is Declining Because of Environmental and Financial Pressures
One Strategy for Dealing with Declining Coal Tar Supply Is Coal Tar/Petroleum Pitch
Because the Refining Industry Uses Pitch to Describe a Number of Products with Varying Properties, Care Must Be Taken in Selecting the Petroleum Component of a Coal Tar/Petroleum Pitch

24. Conclusions, cont.
Coal Tar/Petroleum Pitch Is the Preferred Long Range Solution to the Tar Shortage Because: 1) It Is Economical, 2) Its Performance Has Been Proven, 3) Potential Feedstock Supply Is Plentiful and 4) Product Quality Is Consistent
Coal Tar/Petroleum Pitches with Significantly Reduced PNA Contents Have Been Developed
Coal Tar/Petroleum Pitch Product Development Efforts Will Continue